英文科學(xué)讀本 第三冊·Lesson 16 Birds—More about Legs and Feet

Lesson 16 Birds—More about Legs and Feet

You remember our talk about the woodpecker, Norah? said Fred.

Oh yes, said Norah. "He lives on worms and grubs which eat their way into the woody stems of the trees. He has a wonderful beak for boring into the trees, and a wonderful tongue for catching his prey when he has found out where they are."

Quite right, replied Fred. "Now try and remember something more. These birds live entirely in the trees because their food is in the trees, and in the trees they are extremely nimble. You would be surprised if you could see one of them run up the rough bark of a tree."

Teacher showed us a picture of the woodpecker's foot. It has two toes in front and two behind. Birds with such feet are never seen on the ground. They could only hobble about in a painful, awkward way on a flat surface. But they can run up the rough bark of trees, or climb about the branches with the greatest ease. We call the woodpecker a climbing bird, and the parrot is another member of the same class.

Both birds, you see, live in the trees, and find their food in the trees, and both are fitted in every way for the life they have to lead.

Suppose we go and look at the fowls in the garden now. There they are scratching about on the ash heap. What a mess they are making! Do you know why they are scratching? They are searching for grubs and worms and whatever they can find.

Let us look at their feet. The toes, you see, are short and thick and armed with strong blunt claws. The legs too look strong, as if they were meant for hard work.

Teacher says these legs and feet are given them for scratching in the ground in search of food. Birds of this kind are called scratchers.

Fowls, pigeons, turkeys, pheasants, and partridges all find their food by scratching in the ground. They are all scratchers.

Teacher showed us a picture, said Will, "of a bird with extremely long, slender legs and feet. The legs are so long that the bird looks as if it were on stilts. Teacher pointed out to us the long, sharp, pointed bill, and we saw at once that this must be one of the fishing birds. The sharp bill is meant to catch fish."

These birds always live near the water. Indeed, they walk or wade in the water in search of their prey. We call them waders. Their long stilt-like legs are for this very purpose, and their long necks are to enable them to strike at their prey in the water.

The heron, crane, stork, and flamingo are all waders.

There are, besides the waders, some other birds that live in and near the water, said Fred. "These, however, don't walk in the water, they swim. They are made to swim. Do you know what birds I mean, Norah?"

You must mean ducks and geese and swans, said Norah, " for I have seen them swimming in the lake in the park."

Let me tell you how it is these birds are able to swim so well, said Fred. "If you look at the duck's foot you will see there is a skin or web stretched between the toes. We call it a webbed foot. The webbed feet enable these birds to swim. They are the swimming birds. They swim in the water, and with their shovel-like bills they find their food in the water."

There are some birds, Norah, said Will, "that neither perch on the branches nor climb trees; that neither wade in the water nor swim. In fact, they do not even fly. They can only run. We call them runners. They are great birds."

The largest of them, the ostrich, is often seven feet high. They all have powerful legs for running, but as they do not fly, they have no use for wings. The wings are always very small. The foot has only two short thick toes. It is meant to be a solid support for the runner.

SUMMARY

Climbing-birds have two toes in front and two behind. They live entirely in the trees. The scratchers have strong, blunt claws for scratching in the ground to find their food. The waders have long, stilt-like legs, for walking in the water. Their long necks and bills are to enable them to reach their prey in the water. The feet of all swimming-birds are webbed. The runners have long legs, and short, thick, solid toes.